E-5KL functioned as a protocol droid and was the property of Frelka, an explorer, during the time of the Galactic Civil War.
After the Battle of Yavin, Frelka and E-5KL made a trip to the Bright Jewel system. Their base of operations was Tansarii Point Station, a space station from which they launched expeditions to Station Gamma, a nearby asteroid base. In the year 1 ABY, Frelka and E-5KL journeyed to Station Gamma with the intention of acquiring treasure, only to discover that the station had been seized by the Rak'qua, a warlike tribe of Nautolans. During their exploration, Frelka encountered a Rak'qua warrior, leading to a confrontation that Frelka lost, compelling him to hastily retreat to Tansarii, inadvertently abandoning E-5KL. Subsequently, Frelka encountered a spacer and requested their assistance in retrieving his droid from Station Gamma. The spacer then proceeded to Station Gamma, where E-5KL recounted Frelka's defeat and implored the spacer to eliminate the Rak'qua named Aphotic, who had humiliated Frelka. The spacer fulfilled this request and informed Frelka of his enemy's demise and his droid's safety upon returning. However, Frelka offered a reluctant thanks to the spacer, as he had wished to keep his defeat a secret, and ungratefully suggested he might scrap E-5KL.
E-5KL appeared as a non-player character in the 2003 video game Star Wars Galaxies, a massively multiplayer online roleplaying game that was developed by Sony Online Entertainment and distributed by LucasArts, before it was shut down on December 15, 2011. E-5KL's inclusion in the game was part of the "New Player Tutorial," which was introduced with the release of "Publish 25," also known as the "New Game Enhancements," on November 15, 2005.